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//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
//Example 4
disp("CHAPTER 3");
disp("EXAMPLE 4");
//VARIABLE INITIALIZATION
v_l=866; //in Volts
z_delta=177-(%i*246); //in Ohms
z_wire=1+(%i*2); //in Ohms
//SOLUTION
v_ph=v_l/sqrt(3);
z_star=z_delta/3;
z=z_wire + z_star;
I=v_ph/z; // I_na in rectangular form
//I_na, I_nb and I_nc are same in magnitude and are the line currents for delta connection
//I_na
I_na=sqrt((real(I))^2+(imag(I))^2); //I_na from rectangular to polar form
a=atan(imag(I)/real(I)); //angle in radians
a=a*(180/%pi); //radians to degrees
//I_nb
I_na=sqrt((real(I))^2+(imag(I))^2);
b=a-120; //lags by 120 degrees
//I_nc
I_na=sqrt((real(I))^2+(imag(I))^2);
c=a-240; // lags by another 120 degrees ie.,240 degrees
disp(sprintf("The line currents are %f A (%f degrees), %f A (%f degrees) and %f A (%f degrees)",I_na,a,I_na,b,I_na,c));
//line current lags phase current by 30 degrees, hence (-30)
//I_AB
I_AB=I_na/sqrt(3);
a1=a-(-30);
//I_BC
I_BC=I_na/sqrt(3);
b1=b-(-30);
//I_AC
I_AC=I_na/sqrt(3);
c1=c-(-30);
disp(sprintf("The phase currents are %f A (%f degrees), %f A (%f degrees) and %f A (%f degrees)",I_AB,a1,I_BC,b1,I_AC,c1));
//converting z_delta from polar form to rectangular form
z=sqrt((real(z_delta))^2+(imag(z_delta))^2);
angle=atan(imag(z_delta)/real(z_delta));
angle=angle*(180/%pi);
//line voltages for load or phase voltages for the delta load-
//v_AB
v_AB=I_AB*z;
a2=a1+angle;
//v_B
v_BC=I_BC*z;
b2=b1+angle;
//v_AC
v_AC=I_AC*z;
c2=c1+angle;
disp(sprintf("The phase voltages for the delta load are %f A (%f degrees), %f A (%f degrees) and %f A (%f degrees)",v_AB,a2,v_BC,b2,v_AC,c2));
p_AB=(I_AB^2)*real(z_delta);
p_load=3*p_AB;
disp(sprintf("The power absorbed by the load is %f W",p_load));
p_l=3*(I_na^2)*real(z_wire);
disp(sprintf("The power dissipated by the line is %f W",p_l));
p=p_load+p_l;
disp(sprintf("The total power supplied by 3-ϕ source is %f W",p));
//Answers may be slightly different due to precision of floating point numbers
//END
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